<template>
  <div class="alert">
    <div class="alert-main" v-for="item in notices" :key="item.name">
      <div class="alert-content">{{ item.content }}</div>
    </div>
  </div>
</template>

<script>
import { setTimeout } from 'timers';
  let seed = 0;

  function getUuid() {
    return 'alert_' + (seed++);
  }

  export default {
    data() {
      return  {
        notices: []
      }
    },
    methods: {
      add (notice) {
        const name = getUuid();
        let _notice = Object.assign({ name: name }, notice);
        this.notices.push(_notice);

        // 定时移除，单位：秒
        // const duration = notice.duration;
        setTimeout(() => {
          this.remove(name);
        }, 3000);
      },
      remove(name) {
        const notices = this.notices;
        for(let i= 0; i<notices.length; i++) {
          if(notices[i].name === name) {
            this.notices.splice(i,1);
            break;
          }
        }
      }
    }
  }
</script>

<style>
  .alert {
    position: fixed;
    width: 100%;
    top: 16px;
    left: 0;
    text-align: center;
    pointer-events: none;
    z-index: 9999;
  }
  .alert-content {
    display: inline-block;
    padding: 8px 16px;
    background: #fff;
    border-radius: 3px;
    box-shadow: 0 1px 6px rgba(0,0,0,.2);
    margin-bottom: 8px;
  }
</style>